Inserter systems, such as those applicable for use with the present invention, are typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Also, other organizations, such as direct mailers, use inserts for producing a large volume of generic mailings where the contents of each mail item are substantially identical for each addressee. Examples of such inserter systems are the 8 series, 9 series, and APS™ inserter systems available from Pitney Bowes Inc. of Stamford Conn.
In many respects, the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. The modules and workstations of the inserter system work cooperatively to process the sheets until a finished mail piece is produced. The exact configuration of each inserter system depends upon the needs of the particular customer or installation.
Typically, inserter systems prepare mail pieces by gathering collations of documents on a conveyor chassis. Insert feeders above the chassis release inserts, such as special offers or advertisements, onto the collations as they pass underneath on the chassis. The collations are then transported on the conveyor to an insertion station where they are automatically stuffed into envelopes. After being stuffed with the collations, the envelopes are removed from the insertion station for further processing. Such further processing may include automated closing and sealing the envelope flap, weighing the envelope, applying postage to the envelope, and finally sorting and stacking the envelopes.
The stages of a typical inserter system are depicted in FIG. 1. At the input end of the inserter system, rolls or stacks of continuous printed documents, called a “web,” are fed into the inserter system by a web feeder 10. The continuous web must be separated into individual document pages. This separation is typically carried out by a web cutter 20 that cuts the continuous web into individual document pages. Downstream of the web cutter 20, a right angle turn 30 may be used to reorient the documents, and/or to meet the inserter user's floor space requirements.
The separated documents must subsequently be grouped into collations corresponding to the multi-page documents to be included in individual mail pieces. This gathering of related document pages occurs in the accumulator module 40 where individual pages are stacked on top of one another. Downstream of the accumulator 40, a folder 50 typically folds the accumulation of documents, so that they will fit in the desired envelopes. Then, a buffer transport 60 transports and stores accumulated and folded documents in series in preparation for transferring the documents to the synchronous inserter chassis 70.
On the chassis 70 collations of documents received from the buffer 60 are pushed in the downstream direction by regularly spaced pusher fingers. Typically, document feeders positioned above the chassis and pusher fingers will release additional documents to be included in the collation. Such additional documents are often referred to as inserts and may be special offers or advertisements to be included with a customer's billing statement. To verify that inserts are being properly fed from the document feeders, it is known to position a set of diagonally oriented photo-sensors orthogonal to the feed path of inserts. Such diagonal photo-sensors are typically immediately below the feeders to verify that documents are being fed as expected. Such feeder sensors detect lead and trail edges of documents and confirm that documents are fed onto accumulations as expected.
Downstream of the chassis 70 and insert feeders, the final collations are stuffed into envelopes at insert station 80 and the appropriate postage markings may be added. Finally, the finished mail pieces are sorted by an output sorter 90 to comply with postal requirements for receiving postage discounts.
In an inserter system such as the one shown in FIG. 1 it is desirable that misfed documents and paper jams be detected. One reason is that accurate creation of mail pieces is of importance to users of inserter systems. Another reason is that continued operation during a jam condition can result in the further damaging of mail pieces.
For this purpose, it is known to include a mechanical jam detection device in the chassis 70. This mechanical jam detection device is typically a movable switch positioned above the chassis deck. If paper transported along the chassis deck is prevented from moving, it will usually buckle and crumple in an upward direction. Such buckling will move the mechanical switch suspended above the chassis and a jam signal will be generated. Such a mechanical jam detection switch is sometimes referred to as a jam wire. A disadvantage of mechanical jam detection switches is that they require physical contact with buckling mail pieces. As such, damage may be caused to the buckled document.